Method of determining the volume of the annular space between the casing and wall of boreholes



March 21, 1944. E. P. HALLIBURTON 2,344,771

METHOD OF DETERMINING THE VOLUME OF THE ANNULAR SPACE BETWEEN THE CASING AND WALL OF BORE HOLES .lllffll/ lI/IIIII Filed May 21, 1.945

[710? for Erie Ffiz/Zzzafoi? Patented Mar. 21, 1944 METHOD OF DETERMINING THE VOLUME OF THE ANNULAR. SPACE BETWEEN THE CASING AND WALL OF BOREHOLES Erle P. Halliburton, Los Angeles, Calif., asslgnor Duncan, Okla.

to Halliburton Oil Well Cementing Company,

Application May 21, 1943, Serial No. 487,845

1 Claim.

This invention relates to a method for cementing wells and more particularly to a method for determining accurately the volume 01' cement slurry required to be pumped into a well to fill the annular space between the casing and the wall of the bore hole up to a desired level.

It is common practice to cement casing in oil wells by pumping slurry down through the inside'of the casing and up through the annular space between the casing and the wall of the hole. The use of cementing plugs in such an operation is described in the patent to Perkins, et al., No. 1,011,484 granted December 12, 1911, for Method of cementing oil wells. In carrying on operations of this type the annular space between the casing and wall of the bore hole is often not filled with slurry to the desired level because the operator does not known exactly what the volume of this annular space is. Heretoiore, calculations have usually been based upon the assumption that the bore hole is of substantially uniform diameter, but this is seldom the case.

In accordance with the present invention a method is provided for determining accurately the volume of the annular space between the casing and wall of the bore hole between two selected depths in the well. The method is carried out by determining the amount of fluid pumped into the well which is sufficient to move a body of fluid 01' a difi'erent temperature than that normally prevailing in the well from one depth to another, movement of the fluid of abnormal temperature being detected by the use of a telemetric thermometer.

Accordingly, it is one object of the invention to devise a new and novel method for determining movement of fluid in an oil well, so as to measure the volume of fluid in a confined space therein.

It is another object oi the invention to devise a novel method for filling the annular space between the casing and wall of a bore hole with cement slurry without placing more than the amount necessary to fill the space.

Other objects and advantages reside in certain novel features of the method, as will be apparent from the following description taken in connection with the accompanying drawing in which:

Figure 1 is a vertical cross sectional view of an oil well providedwith casing and with apparatus shown therein for determining the temperature at the bottom of the well.

Figure 2 is a vertical cross sectional view of an oil well the same as Figure 1, but illustrating the thermometer moved to a point up the well from the bottom so as to be located at the level where it is desired that cement slurry shall come up around the casing; and

Figure 3 is a view similar to Figures 1 and 2, but

seen that a well bore is there illustrated at H. 1

The casing I2 is shown in the well in position to be cemented. The top of the casing is provided with a suitable stufllng box and staff arrangement l3 through which an electric cable I4 is passed into the well, the cable extending over a swivelled sheave l5 and on to a drum II.

A thermal responsive element H (such as a resistor having a high temperature cpeflicient) is mounted on the lower end of the cable It and connected to the insulated conductor thereof. By means of a slip ring connection IS onthe drum i8 which makes connection to tire conductor oi the cable I4, the thermal responsive element I1 is connected to an indicating device 19 so that it is possible to observe at the surface of the well, variations in temperature at the element l1. Telemetric thermometers of this type are well known to those skilled in the art, and need not be shown or described here in detail. (See, for example, A Text-book of Physics- Dufi 4th ed. 1916, pages 210 and 395.)

It will be observed that the thermal element 11 may be raised and lowered in the'well as desired and that fluid'may be pumped into the casing through the connection 2| and valve 22, circulating down through the casing and up through the annular space between it and the wall of the bore hole and out through the connection 23, without removing the element I'I from the well.

One way oi. proceeding to carry out the method of the invention is as follows:

The element I1 is lowered to the shoe of the casing as shown in Figure 1. At this time the well will normally be filled with fluid such as drilling mud, which will be approximately at the temperature normally prevailing in the well. With the element I! located at the shoe of the casing a quantity or mud or other fluid of a different temperature than that of the fluid in the well is pumped into the casing and circulated in the direction shown :by the arrows. This quantity of fluid may be at a temperature either above or below that of the fluid in the well. The quantity must be suillcient to maintain a measurable temperature differential long enough to be circulated as'described below.

When the quantity of fluid of abnormal temperature reaches the shoe of the casing its position will be indicated by the instrument IS. The element ll of the thermometer is then raised up the casing to the level shown in Figure 2, which level is that to which it is desired that cement slurry shall be pumped up in the annular space between the casing and the wall of the bore hole. The circulation of the fluid of normal temperature may then be continued in the direction shown by the arrows until the fluid of abnormal temperature reaches the new level or the element II. This position is indicated by'the' instrument l9, due to conduction of heat, through the casing and fluid around the element l During the circulation of the fluid or abnormal temperature from one position in the annular space to the other, the quantity oi fluid of normal temperature pumped into the inlet 2| is accurately measured. This quantity will be equal to the volume of the annular space between the initial position of the element I! at the shoeof the casing to the position shown in Figure 2.

After thus determining the volume of the space which is to be filled with cement slurry the cable ll and element I! may be removed from the well or pulled up into the stufling box and stafl assembly. A quantityof cement slurry equal to that of the volume measured is then pumped into the well in accordance with the usual practice. This operation is illustrated in Figure 3, which shows the slurry 24 being pumped into the well between a bottom plug, 25 (shown at the bottom of the well), and a top plug 26.

Itis obvious that the determination of volume and the placing of the required amount of cemined. Various other modifications may be made without departing from the spirit of the invention or the scope of the annexed claim.

I claim:

The method of-determining the volume oi an annular space between two levels in an oil well 'which consists in placing the thermal responsive element of a telemetric thermometer in a pipe in the well at one of said levels, circulating fluid through the annular space and through said pipe in opposite directions, placing a quantity of fluid in said circulating fluid of a temperature different from that normally prevailing in the well and continuing the circulation until the fluid of abnormal temperature reaches the level at which the thermal responsive element is located, as indicated by the thermometer, moving the thermal responsive element to the other level, continuing the circulation-until the fluid of abnormal temperature reaches the other level, as indicated by the thermometer, and measuring the quantity of fluid pumped into the well in forcing the fluid of abnormal temperature from one level to the other.

ERLE P. HALLIBURTON. 

